Scientists identify virus responsible for parrot disease

Washington, July 31 : Researchers at the University of California, San Francisco have identified a virus that may be responsible for the mysterious parrot disease.

The team led by Joseph DeRisi, PhD, and Don Ganem have discovered a virus called Avian Bornavirus (ABV), a member of bornavirus family responsible for causing encephalitis in horses and livestock, may be behind the infectious parrot disease.

The research team, in collaboration with veterinarians on two continents, was able to isolate this virus in 71 percent of the samples from infected birds.

"This discovery has potentially solved a mystery that has been plaguing the avian veterinary community since the 1970s," said DeRisi, a molecular biologist whose laboratory aided in the 2003 discovery of the virus causing Severe Acute Respiratory Syndrome, or SARS, in humans.

"These results clearly reveal the existence of an avian reservoir of remarkably diverse bornaviruses that are dramatically different from anything seen in other animals," he added.

The team has also developed a diagnostic test for the virus linked to Proventricular Dilation Disease, or PDD, which will enable veterinarians worldwide to control the spread of the virus.

PDD is a fatal disease that causes nervous system disorders in both domesticated and wild birds in the psittacine, or parrot, family worldwide.

The ViroChip technology, developed by DeRisi and Ganem , is a high-throughput screening technology that uses a DNA microarray to test viral samples.

The team recovered virus sequence from a total of 16 diseased birds from two different continents. The complete genome sequence of one isolate was captured using ultra deep sequencing.

The virus they identified is highly divergent from all previously identified members of the Bornaviridae family and represents the first full-length bornavirus genome ever cloned directly from avian tissue. Analysis of the Avian Bornavirus genome revealed at least five distinct varieties.

"This provides a very compelling lead in the long-standing search for a viral cause of PDD," Ganem said.

"With the development of molecular clones and diagnostic tests for ABV, we can now begin to explore both the epidemiology of the virus and how it is linked to the disease state," he added.